Comparison on the anti-inflammatory effect of Cortex Phellodendri Chinensis and Cortex Phellodendri Amurensis in 12-O-tetradecanoyl-phorbol-13-acetate-induced ear edema in mice

Ethnopharmacological relevance: Cortex Phellodendri is derived from the dried bark of Phellodendron chinense Schneid. or Phellodendron amurense Rupr. Traditionally, Cortex Phellodendron Chinensis (CPC) and Cortex Phellodendron Amurensis (CPA) are used interchangeably under the name "Huang Bai" for the treatment of gastroenteritis, abdominal pain or diarrhea. The present study aims to compare the anti-inflammatory effect of ethanol extracts of Cortex Phellodendri Chinensis (ECPC) and Cortex Phellodendri Amurensis (ECPA) in a mouse model of inflammation induced by 12-O-tetradecanoylphorbol-acetate (TPA).

Materials and methods: The anti-inflammatory effect was evaluated by measuring the ear thickness, activity of myeloperoxidase (MPO) and the production reactive oxygen species (ROS). The anti-inflammatory mechanism was explored by determining the protein and mRNA levels of cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6.

Results: The results showed that both ECPC and ECPA significantly decreased the ear thickness, MPO activity and the ROS level in mouse model of inflammation induced by TPA. In addition, ECPC and ECPA also remarkably inhibited the protein and mRNA levels of TNF-α, IL-1β, IL-6 and COX-2. Interestingly, ECPC has better anti-inflammatory effect than that of ECPA.

Conclusions: These results indicate that both ECPC and ECPA have potential anti-inflammatory effect on TPA-induced inflammatory in mice, and ECPC is more effective than ECPA. The anti-inflammatory effect of the herbal drugs may be mediated, at least in part, by down-regulating the mRNA expression of a panel of inflammatory mediators including TNF-α, IL-1β, IL-6 and COX-2.